Projectile propelling apparatus



Jan. 30, 1.934, GERLICH 3,944,883

PROJECTILE PROPELLING APPARATUS Filed Dec. 4, 1930 2 Sheets-Sheet '1Jan. 30, 1934. H, GERLICH PROJECTILE PROPELLING APPARATUS 2 Sheets-Sheet2 Filed Dec. 4, 1930 I DNVENTOR Hermann Gerhch 2 h 62 y%w HIS ATT N EYPatented Jan. 30, 1934 Application December 4, 1930, Serial No. 500,040,

and in Germany December 24, 1929 27 Claims- (CI. 42-76) This inventionrelates to projectile-propelling apparatus, by which an improvedballistic performance may be effected, as regards increase of energy andspeed of the projectile ejected therefrom, and other considerableadvantages obtained. The invention may be practiced in connection withrifled or smooth barrels of firearms, or barrels which are partly rifledand partly smooth bore, as well as with torpedo tubes or other ballisticor projecting engines, operated by compressed air, or gases.

The invention, more particularly, relates to such apparatus in which theprojectiles propelled are provided with peripheral flanges, for thepurpose, among others, of increasing the area upon which the propellinggases will act. In accordance with the invention the construction of thegun or other barrel is improved so that, when a projectile of desiredcharacter is fired, the various improved efiects hereinafter describedwill be obtained. The invention relates to the construction of thebarrel, and also to the special combination of the barrel with theparticular type of projectile described, the barrel and projectile eachcoacting with the other, in the preferred form of device, to provideimproved results due to the interaction of the two. The improvedprojectile per se is not claimed herein, but is the subject of aseparate application.

Objects of the invention comprise the provision of improved combinationsof barrels and projectiles propelled therefrom, and improvedconstructions of barrels, adapted to increase the ballistic performanceand efl'ect of such devices, and to avoid and overcome constructionaldeflciencies and ballistic faults of prior constructions, the existenceof which deflciencies'and defects greatly detract from the ballisticefliciency and the accuracy and precision of results.

Among features of the invention, in its pre- 40 ferred aspects, thefollowing will here be briefly indicated. A flanged projectile isutilized, the flanges alone serving to guide and centre the projectileduring its passage through the bore. The barrel of the projectilepropelling device has a bore which is enlarged (with respect to the boreat the muzzle) at the start of the projectiles travel so as to give amuch increased efiective cross-sectional area, (filled, as to theincreased portion, by the projectiles flanges) over which the gaspressure will act. The bore tapers or decreases in cross section towardsthe muzzle, from some point in its length, so that the projectilesflanges will be depressed, and the material thereof pressed intosuitable recesses provided in the body of the projectile, the latteremerging from the muzzle with a practically smooth form. The flanges areso arranged as properly to guide and centre the projectile, as it passesthrough the barrel, and also to take up the lateral pressure against theflanks of the lands in a rifled or partly rifled barrel. If rifling isused in the barrel, the tops of the lands do not contact with the bodyof the projectile throughout at least the greater part of the travel ofthe projectile through the bore. Thereby, inter alia, resistance to thepassage of the projectile through the bore is greatly decreased ascompared with the case where the rifling bears on the body at all timesor even cuts into the body as is most frequently the case.

Preferably the first section of thebarrel, after the breech chamber, iscylindrical, or practically so, for a distance which may about equal orbe rather greater than that required for the maximum gas pressure, of apropellant, to develop, so that the energy of the propelling medium willbe taken up by the projectile most eiflciently.

When rifling is used the absolute heights oi. the lands, and thearrangement of the lands are preferably chosen according to specialconsiderations, whereby increased projectile energy and so otheradvantages are obtained. Preferably the absolute heights of the lands,in the first part 01 the rifling, will increase in approximatecorrespondence with the pressure exerted on their flanks, per unit ofarea, by the flanges of a pro- 8 jectile passing through this first partof the bore, such increase extending up to approximately (and, ifdesired, beyond) the point in the projectiles travel at which themaximum gas pressure obtains. The absolute heights of the lands, in thisembodiment of the invention, will, as a rule, therefore be greatest inthe neighbourhood of the point of maximum pressure, and will thereafter(preferably after being maintained at maximum height for a distance) andwhen the pressure-ordinates of the pressure-volume-diagram are becomingappreciably shorter, decrease gradually to the required absolute heightadjacent to the muzzle of the barrel. By these and other features ofconstruction various improved results I are attained, which willhereinafter be set forth more in detail.

The cartridge, projectile and barrel are preferably mutually andaccurately adapted to each other specifically in providing aconstructional system, which ensures the required great increase ofpower, energy and speed of the projectile ballistically without undulyincreasing (a) the resulting gas pressures within the bore,

- passage through the barrel;

(b) the length of the barrel, (which moreover may in some cases beshortened) (c) the weight of the fire-arm (which may in some cases bereduced) whilst yet attaining all internal and external ballisticrequirements and a high degree of precision. For this purpose theeffective cross sectional area of the projectile, on which the pressureof the propelling gases is to act, is increased up to a maximum, as isalso the cross section of the bore of the barrel, particularly overthose portions of the bore, through which the ordinates of the pressurecurve will show the highest values so that whilst travelling through themaximum enlarged bore portions the main part of the propellants energyis taken up by the projectile and the latter receives its accelerationwhilst still having a low sectional density. By these means a highlyincreased acceleration of the projectile is rendered possible within thebarrel even with relatively and comparatively low gas pressures, theprojectile being at the same time most effectively centered previous tostarting its forward movement from its seating, and also beingabsolutely reliably and continually guided all along its entire travelwithin the barrel, and the projectile prior to its departure from thebarrel having its flanges regularly depressed, with the result that ahigh sectional density and a ballistically favourable shape of theprojectile in conjunction with an extremely high degree of axialstability is ensured for the projectile during its trajectory throughatmosphere after a steady and consistently uniform departure from themuzzle of the barrel.

The projectiles preferably comprise a body having two or more axiallyspaced circumferential flanges, said body being preferably of a calibrenot greater than, in the case of a smooth bore barrel, the muzzlediameter of the barrel from which it is to be fired, or in the case of arifled barrel not greater than (but substantially equal to) the landsbore calibre at the muzzle. The flanges are each of a diameter equal toor slightly greater than that of the largest bore, or groove bore,diameter of the barrel and behind each flange is provided in the body ofthe projectile a cannelure large enough to receive wholly the flange infront thereof as the flange is depressed during the travel of theprojectile through the barrel. The front and rear flanges are preferablyrespectively disposed at substantially equal distances in front of andto the rear of the centre of gravity of the projectile. The flanges areof large diameter as compared with the diameter of the body of theprojectile and serve, firstly, for reliably and correctly centering theprojectile previous to being fired and also during its entire secondly,for effectively sealing the bore against the propelling gases during theprojectiles movement through it, and thirdly, for reliably and steadilyguiding the projectile all along its entire course within the barrel andat the same time preventing all axial tilting movements and radialdisplacements of the axis of the projectile and projectile nutationsduring the projectiles movement within the bore of the barrel whilsttaking up at the same time the effective and specific pressure on theflanks of the lands in connection with rifled barrels. The projectilethus maintains a perfect equilibrium within the bore from its start toits departure from the muzzle and its centre of gravity of theprojectile is thus steadily, continu- This is of extreme importance asregards the steady and concentric progressive squeezing back and down ofthe flanges. In the case of fully rifled arms the front of the foremostflange of the projectile is congruent with the shape and inclination ofthe lead from the breech chamber into the rifled part of the bore (i. c.with the rear ends of the lands), against which it bears. This appliesboth to fire-arms and the like in which a single complete cartridge isused, in which the projectile is tightly inserted in the cartridge neck,and also to fire arms in connection with which projectile and cartouchesare kept separate.

The process of displacing the flange-material takes place locally onvery short axial stretches on the circumference of the projectilewithout any deformation of the projectile which would have anunfavourable effect by shifting material radially and eccentrically thusincorrectly displacing the centre of gravity, which should be avoided.The rear edge of the rearmost cannelure behind the rearmost flange ofthe projectile should axially be placed slightly away from the rearmostcross section of the cylindrical portion of the projectile body proper(whether having a boat tail or cylindrical rear end.

In order that the invenion may be more clearly understood attention ishereby directed to the annexed drawings forming part of this applicationand illustrating diagrammatically by way of example certain embodimentsof the invention.

Figs. 1 to 3 of the annexed drawings show diagrammatically boat-tailedrifle bullets of the kind referred to.

Fig. 4 shows a complete rifle cartridge with the bullet tightly held inthe neck of the cartridge case.

Figs. 5 to 7 show diagrammatically ordnance projectile in which theprojectile flange-rings may be slotted as in Fig. '7 in the sense of thetwist or the angle of the rifling for the lands of the rifled barrel.

Fig. 8 shows in sectional elevation the chamber and the lead into therifled portion of a barrel according to this invention whereas Fig. 9shows an elevation of the bore of the barrel, seen in the direction ofthe arrow.

Figs. 10 and 11 illustrate diagrammatically in part longitudinal sectionand end elevation respectively a further and slightly modified form ofbarrel.

Figs. 12 to 15 show diagrammatically and exaggeratedly further forms ofbarrels according to this invention in longitudinal sectional elevation.

In the drawings s indicates the centre of gravity of the projectile anda and b the rear and front projectile flanges respectively, betweenwhich is axially practically centred the centre of gravity of theprojectile. The diameter of the cylindrical portions of the projectilebody, may, where required, as for instance for small arm projectile beslightly in excess of the lands calibre of the barrel at the muzzle.

For smooth bore arms and the like, as for example in connection withsmooth bore mine throwing and similar guns and for torpedo lancing tubesthe projectiles may be provided with flanges of lead leather or similarplastic or readby deformable materials. In the case of rifled barrelsthe flanges may take up alone the entire specific pressures on theflanks of the lands thus efiecting the rotation of the projectile. Whenfiring or propelling such projectiles from barrels with a progressivetwist of the rifling and if for instance but two flanges are provided,these flanges may, if required, be preferably placed at a very shortaxial distance from each other and axially on opposite sides of thecentre of gravity of the projectile.

In order to obtain -the required increase of the ballistic effect withprojectiles such as described the barrels according to this inventionand from which the projectiles are fired are constructed and bored inthe following manner. In the case of rifled arms the lands, which are,as far as possible, reduced in number, are made as narrow as possibleand are preferably not executed with sharp upper edges and may be alsorounded off with a slight radius at their bases. The land calibre may bewidened over a certain portion of the projectiles travel within the borepreferably along the first portion thereof. The lands caliber may thusand over anydesired length of the bore or of the projectiles travel becylindrical and of constant diameter, but appreciably widened inrelation to the diameter of the body proper of the projectile, and thenstarting from a certain and suitable point of the bore graduallytapering down towards the muzzle end of the barrel conically,parabolically or according to any suitably plotted curve, or may betapering down and narrowing in this way right from the very start of therifled portion of the barrel, i. e. from the breech chamber end onwards.If required, the land calibre may be widened to a maximum extent buttapering down towards the muzzle over the first portion and any'desired'length of the projectiles travel and then from a certain andsuitable point onwards be kept less wide with a constant diameter,although with a diameter appreciably larger than that of the body properof the bullet, after which the lands bore again tapers down to thenormal calibre adjacent the muzzle as is, of course essential. The landsmay advantageously, tapered towards the lead into the rifled portion ofthe barrel, taper wedge-like laterally as well as on their top partswhereby they will cut more easily and more gradually into the abovementioned projectile flanges without a too forcible, sudden andimmediate pressing back and rearward displacement of the flangematerial. The first taper or inclined top surfaces of the lands willsubtend a greater angle at the axis of the bore than the main taperedportion of the lands bore as it is of course shorter axially than thelatter. The gradual narrowing of the lands calibre and the gradualreduction of the diameter of the groove bore will in the front portionof the barrel and near the muzzle effect the pressing back and levellingdown, of the projectile flange material, into the cannelures behind theflanges, which become filled up level practically with thesurface-contour of the body proper of the projectile.

ing gas pressures without risking any squeezing away or shearing off ofthe projectile flanges.

An appreciably widened cylindrical and also a widened conical orparabolic lands bore over' a more or less lengthy portion of theprojectiles travel within the barrel and also a lands bore with landsrather low and of wider calibre at the chamber end and graduallydecreasing in calibre, result in increase of effective cross sectionalarea and in a reduction of the resistance which is offered to theprojectile when being pressed into the rifled portion of the bore, andalso in a reduction of the gas pressure due to reduction of resistance;also in a reduced and more gradual and more uniform and still morecontrollable deformation of the projectile flanges result from theseimprovements especially over those sections of the bore over whichmaximum gas pressures and highest accelerations prevail; also there isless wear of the bore and especially of the lands over the said sectionsof the bore as well as appreciably less heating of the lands owing totheir surfaces exposed to the action of the flame of the propellingcharge being greatly reduced in area and owing to the considerablyfacilitated transmission of heat under these more favourable conditionsfrom the top parts of the lands of the rifling, (which are the most exposed to the flame of the burning charge and the propelling hot gasesand which therefore are taking up heat most intensively), to the mass ofthe barrel itself. This is indeed a feature, which is of specialimportance in practice with regard to the life of the barrels inquestion.

The initial height f the lands may be reduced over the portion of thebarrel having the largest groove diameter to 50% or less which thatheight of the lands would have at this part of the bore if the landscalibre was constant throughout the barrel and the same as the minimumlands calibre. The maximum cylindrically enlarged land-calibre, or, ifrequired, also a gradual reduction of the widened land caibre, couldpractically be extended over that length of the projectiles travel overwhich the groove calibre is also widened substantially cylindrically toa maximum with a constant diameter etc. The ratio of the widening of theland calibre and the absolute height of the lands along this part of theprojectiles travel may incidentally be regu'ated according to the curveof the specific pressure with which the projecting flanges are bearingon the flanks of the lands, which preferably may also be the .case inthe second and further portion of the bore, over which the groovecalibre is gradually narrowing according to a suitable taper.

The groove diameter of a rifled barrel is enlarged to the best possibleextent from the rearmost portion of the bore proper, i. eubreech chamberend of the barrel. This very marked widening of the groove bore is to beeffected according to conditions prevailing specifically and should bemade as large as possible. The grooves should at the same time be madeas broad as possibe with a corresponding narrowing of the lands. inorder to obtain the greatest possible increase of effective bore crosssection. Over the first portion of the bore which is dimensionedaccording to specific conditions prevailing and which should be made aslong as possible, the groove bore should preferably be kept practical-1y constant with a maximum diameter (as compared with the groove orlands calibre at the muzzle of the barrel) in such a. manner that alongthis first portion of the bore the groove bore is practicallycylindrical, and that starting tive projectile cross sectional areaalong this portion of the projectiles travel, which is decisive for theabsolute amount of work or energy taken up by the projectile, so thatthe ballistic effect and the dynamical eificiency of this method becomesvery great under these'circumstances.

The first portion of the bore (-in armed bore the lands bore as well asthe groove bore) enlarged to a maximum extent in the manner described,then merges gradually and smoothly into a second bore portion, (the boreof which is narrowing conically or parabolically or tapering downaccording to some other specifically suitable curve and the proportionallength of which portion is determined by the specific conditions andrequirements of each case. In the last portion of the projectfles travelnear the muzzle of the barrel, over which the ordinates of the gaspressure-and accelerationcurve only show comparatively low values, thegroove bore may be reduced to a normal and constant size and the landsbore at the same time may be of normal and constant calibre. This lastand cylindrical portion of the bore of normal and nominal size may shoethe usually standard and con stant dimensional diiiercnces and relationsbetween groove diameter, lands diameter and bullet diameter-asheretofore usual in rifled arms. The length of this last normaly rifledand bored portion of the bore near the muzzle may be determined adlibitum and according to specific requirements.

A portion of the projectiles travel corresponding approximately to onequarter or so of the length of the twist of the rifling or to aboutdouble the projectile length or about five to six times the axialbearing length of the projectile may as a rule be taken as amplysufiicient length for this last normally bored portion of the bore. As arule this portion may be cut down in length to about 5% of the totallength of the projectile's travel Within the barrel.

The projectile consequently and whilst travelling along the entire axiallength of the bore will be gradually pressed into a form and shapeexceedingly favourable and effective ballistically- The completedisappearance of the projecting flanges and the simultaneous levellingup of the cannelures is finally effected Whilst the projectile ispassing through the last portion of the bore. A projectile of standardweight f or a given calibre then leaves the muzzle of the arm with astand- ,ard sectional density, whereas its initial speed,

i. e. its muzzle velocity, is most considerably and decisively increasedas compared with the muzzle velocity of a normal projectile fired from ausual barrel by the very highly increased absorption of energy withoutany corresponding increase of the accelerating gas pressures or anyundue absolute increases of pressure whatsoever. Even with increasedprojectile weight and increased sectional density the muzzlevelocity ofthe projectile fired from a barrel according to this'invention will bethe same as or even ,higher than .is the case with a projectile ofstandard or of even considerably lighter weight fired from acorresponding barrel of standard construction, this being the case evenwhen using practically same and identical gas pressures in both types ofbarrel. Such a projectile warrants at the same time a high degree ofaxial stability and steadiness of flight under these conditions. A mostexcellent value of form and an extremely high ballistic coeflicient maybe realized witha projectile fired with such an extremely increasedinitial speed, the trajectory of which projectile becomes more rasantand exceedingly flat owing to its highly increased velocity and extremeranging power (enormously reduced. times of flight). Such a projectile,whilst possessing excellent precision and accuracy, renders possible anextreme and actually decisive increase of its striking energies, i. e.also its striking velocities, and threeby an enormous increase of itsdestructive and piercing efiects. In connection with these increasedballistics due attention should be paid to the importance of reachingspecifically critical speed-limits and also to the fact, that at thesehigher bullet-speeds air resistance is not increasing at the same highrate as is the case within lower bullet speed-limits.

Fig. 8 shows the construction of the barrel with a cylindrical groovebore of maximum diameter over the first portion of the bore, the landscalibre in this first portion of the bore being also considerablywidened narrowing down gradually along the bore in the manner describedto the nominal. or minimum lands calibre, which same as the groove borewhich is also narrowed down towards the muzzleremains constant in thevery last portion of the bore near the muzzle. The lands calibre may bebored as shown in Fig. 8 so that it is narrowing immediately from theabrupt ends of the lands with any suitable taper to the lands calibre atthe muzzle or, as shown in Figs. 10 and 11 which illustrate aconstruction of the barrel with an appreciably widened cylindricalgroove bore of constant maximum diameter over the first portion of thebore, the lands calibre may be appreciably widened over this firstportion of the bore with a constant maximum lands bore diameter. In thisinstance therefore--the bores of the grooves g and lands I over thisfirst portion of the bore are cylindrical and axially parallel. This isthe modus of construction, which as a rule guarantees the maximumincrease of ballistic effect.

Fig. 12 shows diagrammatically in longitudinal section a rifled barrelhaving a groove bore with an enlarged cylindrical section 11 at thebreech chamber end of the bore, a cylindrical section 7' at the muzzleend 'of the bore, these sections be ing joined together by a taperedsection It in creasing in diameter'towards the end where it meets thecylindrical section. The lands bore is constant over a portion Zextending a distance from the muzzle and then increases in calibre overa part 111. gradually at a difierent rate of taper to the park k of thegroove bore and relative to the bore axis, then the lands bore has anenlarged cylindrical part 12 after which it is again gradually enlargedtowards the breech chamber over a part 0 at a difierent rate of taperrelative to the bore axis than the tapered portion k.

Fig. 13 shows a similar groove bore to Fig. 12 but the lands bore inthis case has not the part 0 shown in Fig. 12, the lands bore remainingof constant calibre right up to the breech chamber.

Fig. 14 shows a partially smooth and partially rifled barrel having agroove bore as in Figs. 12 and 13 but here the lands bore portion mterminates between the ends of the bore in a part 1) somewhat similar tothe part 0 in Fig. 12.

Again Fig. 15 shows a similar groove bore to Figs. 12, 13 and 14, buthere the lands bore increases in calibre in a straight taper q rightfrom the inner end of its muzzle section I to the breech chamber end ofthe bore.

The guiding of the projectile is effected only and exclusively by theprojecting flanges a and b, that is to say only by their bearing on thegroove surfaces 9 and on the lands f, as far as these are cutting intothe projecting flanges, without involving the necessity of theprojectile-body proper to come into bearing contact even only with thetopparts of the lands and without being required to be guided thereby.The reliable and efiicient guiding of the projectile required forreliable and consistent precision is effected by a couple or a pluralityof narrow annular areas separated from each other by some distanceinstead of following the usual style-especially in connection with metalpatched rifle bullets-of guiding the bullet on a single longer andconsiderably larger bearing surface. This, and also the fact that thelands (which vary in absolute height as previously stated approximatelyaccording to the lateral pressure curve) have higher flanks than usualand participate to a much greater extent in the guiding of theprojectile-are fundamental and principal differences between theimproved and usual method of guiding the projectile and are veryimportant factors in practice.

By this method of guiding and supporting the projectile drawbacks ofguiding on an axially longer and greater coherent single surface of theprojectile are most effectively eliminated and indeed so without any newdisadvantages resulting. Moreover using very high projectile velocitiesand an appreciably widened land calibre ensures that practically allmetallic fouling of the bore by the flange-materials of the projectilesis effectively avoided or reduced.

As an example of the enormous advantages and decisive increases inballistic performance and effects which may be obtained by the describedconstructions a Cal. 7 mm. rifle may for instance be taken. This riflefires the well known 7 mm. Mauser military cartridge, which in a barrel74 cms. or 29%" long imparts to its 10 grammes (154 grs.) Spitzer bulleta muzzle velocity of about 860 m./sec. or just about 2,830 ft./sec. witha powder charge of 3.25 grammes. Corresponding to a bullet diameter ofabout 7.2 mm. the effective cross sectional area is in this instancepractically 40 mm With a flange projecting around the circumference ofthe body of the bullet for instance 1 mm. the diameter becomes increasedto 9.2 mm. corresponding to cross sectional area of 66 mmfi. This, ascompared with the 7.2 mm. bullet, represents an increase of crosssectional area of 26mm. or By making the lands narrower than usual andas shallow as possible only a minimum of this increased effective areais, in the early stages of the projectiles movement, lost by flangedisplacement by the lands.

Especially in view of the fact that along the first portion of the bore,which may be extended over a very considerable length of the entirebore, the effective cross sectional areas of the bore and the bullet maybe increased almost ad libitum to an effective maximum, as described,and since all along this first portion of the bore and the bulletstravel the absolute and mean effective gas pressures are by far thegreatest and moreover, if the propelling charge or the developedgas-volume is increased approximately in correspondence with and inrelation to the increase of the cross sectional area or volume, a verygreat and most decisive increase of bullet energybe it with regard tothe weight or the velocity factor or with regard to both-may be actuallyrealized over the same length of the projectiles travel or with the samelengthor even shorter lengthof barrel without abnormally and undulyincreasing the pressure acting upon the projectile. This will beespecially so if a modern propellant of sufficient cubic density ischosen which burns specifically more quickly than usual propellants andwhich will be especially eflicient if specifically tuned up incorrespondence with the greatly increased effective cross sectionalareas and the higher rate of increasing the volume behind the projectileowing to a very high increase of bullet acceleration. This enormousincrease of bullet energy thus actually and practically obtained may besuitably utilized as required in every case, and whilst keeping thepressures within usual and normal limits, either by proportionatelyincreasing the absolute weight of the projectile in connection with thesame muzzle velocity, or especially by most considerably and decisivelyincreasing the muzzle velocity of a projectile of standard weight and ofstandard ultimate sectional density. This very great increase of energyof theprojectile or of its ballistic power and performance may thus andaccording to the method described be practically and actually utilizedwithin very wide limits and indeed could be realized with a cartridgeand in a weapon of specifically normal dimensions and standard weight;or even with such a cartridge but with a shorter barrel by employing aspecifically sharper burning and sufiiciently dense propellant.

This invention may of course be applied-and especially if certainconstructional details are correspondingly alteredto smooth bore arms,the bore of which is executed either cylindrically at the start with anenlarged inner diameter or tapered and narrowing down according to asuitable, curve right away from the very chamber. The smooth bores maybe bored in a manner analogous either to the groove bores or the landsbores of the rifled barrels described, the bores of which may beexecuted with diameters narrowing down towards the muzzle according toany desired and suitably plotted specific curve-and indeed so eitherwith regard to the entire length of the bore or only with regard toportions thereof and with regard to the groove bore as well as to thelands bore. Besides barrels may be executed ad libitum with any desiredcombination of the described types and styles of boring for certainspecific purposes and under certain conditions, for example barrels maybe made, which are rifled over cerameter at this part, the groove borebeing, for the purpose of explaining its form, imagined in all caseswithout the lands whether the bore is or is not rifled. By the term"taper used in the claims is meant either a straight taper or anysuitable curved taper.

1. Projectile propelling apparatus comprising a barrel having a breechchamber and a bore consisting of three sections, namely, a muzzlesection remote from the breech chamber and of substantially normaldimensions for the projectiles for which the barrel is designed, asubstantially cylindrical section adjacent to and following the breechchamber, such section being of enlarged diameter as compared with thesubstantially normal diameter of the muzzle section, and suchcylindrical section extending along the barrel for a substantial lengthsufflcient to enable a projectile passing through this section to besubjected whilst therein to the action of the propelling gases duringthe time they are at their higher pressures, and a section connectingsuch substantially cylindrical section to the muzzle section anddecreasing (from the cylindrical section end of the barrel to the muzzlesection end thereof) gradually from the diameter of the said enlargedsubstantially cylindrical section to the diameter of the muzzle sectionsaid connecting section extending over a relatively long portion of thebore.

2. Projectile propelling apparatus comprising a barrel having a breechchamber, a groove bore consisting of a muzzle section having a crosssectional area substantially normal for an ordinary unfianged projectilehaving the calibre of the body of a flanged projectile to be used withthe said propelling apparatus, a substantially cylindrical section atthe breech chamber end of the barrel, such section being of a crosssectional area greater than the muzzle section and in excess of that ofthe body of the said projectile and following the breech chamber, and asection connecting said substantially cylindrical section with themuzzle section, the cross sectional area of such connecting sectiondecreasing (towards the muzzle section) from that of the cylindricalsection of the barrel to that of the muzzle section of the barrel, saidconnecting section being relatively long as compared with the saidenlarged cylindrical section, said barrel having rifling and the landsbore being of a diameter substantially normal for the said projectile atthe mouth of the muzzle of the barrel and being increased in diameterfrom such mouth towards the breech end of the latter.

3. Projectile propelling apparatus comprising a breech chamber, and arifled barrel comprising three sections, namely, a muzzle section remotefrom the breech chamber and the calibre of the lands bore of which issubstantially equal to the diameter of the body of the projectile forwhich the barrel is designed whilst the absolute heights of the lands inthis section are substantially those which would be normal for anordinary constant bore diameter barrel having a cylindrical lands boreof the said calibre, a substantially cylindrical section adjacent andfollowing the breech chamber, the groove bore of such section being ofenlarged diameter as compared with the normal diameter of the muzzlesection, and such cylindrical section extending along the barrel for alength sufficient to enable a projectile passing through this section tobe subjected to the action of the propelling gases from the time theycommence to act to and during the time when the gases are at theirhigher pressures, and a section connecting such 'substantiallycylindrical section to the muzzle section and the groove bore of whichdecreases radually from the diameter of the said substantiallycylindrical section to the diameter of the muzzle section, and the landsbore of the barrel being increased in calibre towards the breech chamberend of the barrel.

4. Projectile propelling apparatus comprising a breech chamber and arifled barrel having a groove bore formed in three sections, a muzzlesection having a cylindrical groove bore normal for the calibre ofprojectile for which the barrel is designed, a substantially cylindricalsection at the breech chamber end of the barrel, and the diameter ofwhich is greater than the diameter of the groove bore of the muzzlesection, said cylindrical section being of a length suflicient to enablea projectile passing therethrough to be'subject whilst therein to theaction of the propelling gases during the time they are'at their higherpressures, and a section. connecting said substantially cylindricalsection with the muzzle section, the diameter of which section decreasesfrom the diameter of thecylindrical section of the barrel to thediameter of the muzzle section, and the lands bore being in the muzzlesection of normal diameter for the said projectile, but graduallyincreasing in diameter from the muzzle section of the barrel towards thebreech end of the barrel and the lands ending and merging into thegroove bore between the muzzle section and the breech end of the saidcylindrical section.

5. Projectile propelling apparatus comprising a breech chamber and abarrel having a groove bore including a muzzle section of a crosssectional area substantially normal for the projectile which the barrelis designed to project, a cylindrical section adjacent to and followingthe breech chamber, said cylindrical section being of such a length thatduring the movement of the projectile therethrough the latter issubjected to the pressure of the propelling gases from the commencementof their action until they attain their maximum pressure, and suchcylindrical section also being not less than 20% greater in crosssectional area than the body of the projectile, and an intermediatesection connecting said cylindrical and muzzle sections and decreasingin cross sectional area from the former section to the latter section,lands extending along the bore of said barrel, and the lands boreincreasing in calibre from normal calibre at the muzzle section endtowards the breech chamber end of the barrel until the lands finally endand merge into the'groove bore between the breech chamber end of thesaid cylindrical section and the muzzle section, and said lands havingtheir tops and sides bevelled at the ends nearest the breech chamber.

6. Projectile propelling apparatus comprising a rifled barrel having, inaddition to the breech chamber, a groove bore which is, at the mouth ofthe barrel, of a diameter substantially normal for the projectile forwhich the barrelis designed, said groove bore being of enlarged diameterat the breech chamber end thereof and being reduced, between its ends,from the said enlarged diameter to the said normal diameter, and thelands bore being also enlarged towards the breech chamber end of thebarrel and the largest calibre of the lands bore being greater than thecalibre of the body proper of said pro- 1 jectile, and the lands merginginto .said groove 1 barrel, of a calibre substantially equal 'to thatchamber, a rifled bore having a muzzle section' of ,the body of theprojectile for which the barre l is designed, the groove bore diameterat the muzzle being substantially normal for such a lands calibre, andsaid groove bore being of enlarged diameter at the breech chamber endthereof and being reduced, between its ends, from the said enlargeddiameter to the saidnormal diameter, and the lands bore being alsogradually enlarged in calibre from a point nearer the mouth of thebarrel than the breech chamber end thereof and in a direction towardsthe breech chamberend of the barrel, such lands calibre enlargementbeing at a rate of taper (relative to the axis of thebore) difierenttothatat which the groove bore increases.

8. Projectile propelling apparatus comprising a breech chamber and arifled barrel having a.

bore which is, at the muzzle of the barrel, of a diameter substantiallyequal to that of the body of the flanged projectile for which the barrelis designed, the groove bore being of enlarged diameter at the breechchamber end thereof and being tapered, between its ends, from the saidenlarged diameter to the said muzzle diameter, said tapered portion ofthe groove bore extending over a relatively long portion of the barrel,and the lands bore being also enlarged towards the breech chamber end ofthe barrel, and the largest calibre of the lands bore being greater thanthe calibre of the body proper of said projectile, and the lands merginginto said groove bore between the muzzle and enlarged ends thereof.

9. Projectile propelling apparatus comprising a barrel provided with, inaddition to a breech the lands bore calibre at the mouth of which issubstantially equal to the calibre of the body of a flanged projectilefor which the barrel is designed and the groove bore diameter of whichis substantially constant throughout the section and substantiallynormal for said lands bore calibre, and a further section between thebreech chamber and the muzzle section and the groove bore diameter ofwhich is enlarged gradually in diameter, from where it joins the groovebore of the muzzle section, in a direction towards the breech chamber,the lands bore of the barrel also being gradually enlarged in calibre ina direction towards the breech chamber end of the barrel and to a pointat which the lands are of an absolute height which is greater than theheight of the lands at the mouth of the rifled muzzle part of thebarrel, and the rear part of the lands bore (1. e. the part between thesaid point and the lands ends nearest the breech chamber) being againgradually and further enlarged in calibre with a diflerent angle oftaper towards the breech chamber.

10. Projectile propelling apparatus comprising a barrel having a breechchamber and a rifled bore, in which gas pressure is adapted to increaseto a maximum during the first portion of a projectiles traveltherethrough, and to thereafter decrease, the lands bore thereof being,at the muzzle end thereof substantially equal in calibre to the calibreof the body of the projectile for which the barrel is designed, and thegroove bore thereof being, at the muzzle end thereof, substantiallynormal for such a lands bore, said lands and groove bores being,adjacent to the breechchamber end of the bore, of enlarged dimensions ascompared with their.muz-

zle dimensions, the lands increasing in heightg from the beginning ofthe rifling, in approximate correspondence with the lateral pressure perunit of bearing area exerted on their flanks.

.by' a projectile passing'through the barrel, up to approximately thepoint of' the projectiles travel at which the maximum gas pressureobtains, at which point the heights of the lands are greater than at themuzzle, .the heights of the lands subsequently decreasing, in thedirection of the muzzle.

11. Apparatus for propelling a flanged projectile and comprisinga'barrel having a breech provided with a further section between thebreech'chamber and the muzzle section and the groove bore diameter ofwhich is enlarged at the breech chamber end thereof and which sectiongradually decreases in diameter to the point Where it joins the groovebore of said muzzle section, the lands bore of the barrel also beingenlarged in calibre in a direction from the muzzle end portions'formingbearing surfaces adapted to be engaged by a flange of said projectile,and the said bore being at its largest part of a cross sectional area atleast 20% larger than that of the said muzzle section at its mouth.

12. Projectile propelling apparatus comprising a breech chamber and arifled barrel the lands bore of which is at the mouth of the barrelsubstantially equal to the calibre of the body of the projectile forwhich the barrel is designed, such barrel having,a groove bore in threesections, namely, a muzzle section remote from the breech chamber and ofa diameter substantially normal for said lands bore calibre, asubstantially cylindrical section adjacent to and following the breechchamber, such section being of enlarged diameteras compared with thediameter of said muzzle section, and such substantially cylindricalsection being of a length sufficient to enable a projectile passingtherethrough and whilst therein to be subjected to the action of thepropelling gases from the commencement of their action to and during thetime they are exercising their higher pressures, and a single sectionconnecting said substantially cylindrical section to the muzzle sectionand decreasing, in a direction from thebreech chamber end thereof to themuzzle end thereof, from the diameter of said enlarged cylindricalsection to the diameter of the muzzle section groove bore, and the landsbore increasing in calibre, in a direction from the muzzle sectiontowards the breech chamber, to a point from which the lands are ramped(ie. the lands bore is again gradually increased in calibre with adifferent angle of taper in a direction towards the breech chamber endof the bore).

13. Projectile propelling apparatus comprising 4 a barrel having ridingand also having in addition to a breech chamber, a muzzle section thelands bore at the mouth of which is of a calibre substantially equal tothat of the body of the pro-' jectile for which the barrel is designedand the groove bore diameter of such muzzle section being substantiallyconstant and normal for said lands bore, and a further section betweenthe breech chamber and the muzzle section thegroove bore diameter ofwhich is enlarged at the breech chamber end thereof and graduallydecreases to the point where this section joins the groove bore of themuzzle section, the lands bore being also enlarged in calibre in adirection towards the breech chamber end of the barrel at a slower rateof taper relative to the axis of the barrel than that at which thegroove bore diameter is increased, the said enlargement of the landsbore continuing We point between the ends of the lands at which theabsolute height of the lands is greater than the height .of the lands atthe muzzle, the lands calibre subsequently being again graduallyincreased (the absolute height of the lands being consequentlydecreased) towards the origin of the lands where the latter-merge intothe groove bore between the ends of the tapered section thereof.

14. Apparatus for propelling flanged projectiles comprising a rifledbarrel having a groove bore, including in addition to the breechchamber, three sections, namely, .a substantially cylindrical sectionadjacent and following the breech chamber and having a cross sectionalarea at least 20% greater than that of the projectile body for which thebarrel is designed and substantially corresponding in groove borediameter with the diameter of peripheral flanges on the projectile, suchcylindrical section being of a length sufficient to enable thepropelling gases to act on the projectile (including the flanges) whileit is therein, from the commencement of their action until they attaintheir maximum pressure, a muzzle section the groove and lands bores ofwhich are cylindrical and in which the lands bore calibre issubstantially equal to the calibre of the said projectile body, and asingle intermediate section connecting said cylindrical and muzzlesections together and the groove bore of which decreases gradually indiameter from the enlarged cylindrical section to the muzzle section,the lands bore calibre gradually, and at a slower rate of taper relativeto the barrel axis than the said groove bore, increasing through thesaid intermediate section towards the breech chamber end to a point atwhich the lands are of an absolute height which is greater than theabsolute height of the lands at the muzzle section of the barrel, andthe calibre of the lands bore then, from a point nearer to the breechchamber than the first named point and within the cylindrical section ofthe groove bore, being again gradually increased towards the breechchamber, and the lands having their sides bevelle off towards theirbreech chamber ends. 1 i

15. Projectile propelling apparatus comprising a barrel having a breechchamber and in addition to the latter a bore consisting of three (only)end to end coaxial sections, namely, a cylindrical muzzle section remotefrom the breech chamber and of substantially normal dimensions for thestandard calibre of the projectile body proper for 1,944,aes

which the barrel is designed, a cylindrical section adjacent to andfollowing the breech chamber, such section being of enlarged diameter ascompared with the substantially normal diameter of the muzzle section,and an intermediate section connecting such cylindrical section to'the'muzzle section and decreasing continuously in its diameter according toany suitable continuous taper (from the end of the enlarged cylindricalsection of the bore to the beginning of the practically normal muzzlesection thereof) from the diameter of the said enlarged cylindricalsection to the diameter of the muzzle section and such intermediatesection extending over a relatively large' portion of the bore ascompared with said enlarged cylindricalsection and decreasing graduallyand steadily in its diameter along said taper and without abrupt shortand relatively steep contractions or conical transition chokes.

16. Projectile propelling apparatus comprising a barrel having a breechchamber, a groove bore consisting of a muzzle section having a crosssectional area substantially normal for a projectile having the calibreof the body of the projectile to be used with the said propellingapparatus, a substantially cylindrical section at the breech chamber endof the barrel, such section being of a cross sectional area greater thanthe muzzle section and in excess of that of the body of the saidprojectile and following the breech chamber, and a section connectingsaid substantially cylindrical section with the muzzle section, thecross sectional area of such connecting section decreasing from that atthe forward end of the cylindrical section of the barrel to that of theinner end of the muzzle section of the barrel, said barrel havingrifling and the lands bore being at the muzzle section of the barrel ofa calibre substantially normal for the said projectile and beingincreased in calibre towards the breech end of the barrel, and theabsolute heights of the lands being at a part of the lands between theirends greater than in the muzzle section of the barrel.

1'7. Projectile propelling apparatus comprising a rifled barrel havingin addition to a breech chamber and between the latter and its forwardextremity a rifled bore, the lands bore of which is, at the muzzle ofthe barrel, of a calibre substantially equal to that of the body of theprojectile for which the barrel is designed whilst the groove borediameter is at this part substantially normal for such a lands calibre,said groove and lands bores being with respect'to the muzzle end of thebore enlarged in diameter and calibre respectively at different rates oftaper relative to the axis of the barrel and in a direction from the Imuzzle towards the breech chamber, the lands being, nearer their breechchamber ends than their muzzle ends of a maximum absolute height whichis greater than the absolute height of the lands at the muzzle of thebarrel, the said lands varying in absolute height approximately inproportion to the curve of lateral pressure per unit of bearing areawhich would be exerted by the flanges of a flanged projectile on theflanks of the lands.

18. Projectile propelling apparatus comprising a rifled barrel having inaddition to the breech chamber and between the latter and its muzzle, arifled bore the lands bore of which is at the mouth of the barrel of acalibre substantially equal to 7 in diameter throughout a part of itslength and terminating in a cylindrical section in front of the breechchamber and of a larger diameter than the groove bore at the mouth ofthe barrel, and said lands calibre also increasing towards the. breechchamber end of the barrel gradually over the greater part of its lengthand later and nearer the breech chamber end of the barrel increasing incalibre ata greater rate of taper relative to the axis of the bore thanbefore, such increases of the lands bore calibre and the correspondingheights of the lands being regulated in approximate accordance with thecurve of lateral pressure whichwould be exerted on the flanks of thelands by the flanged projectile.

19. A projectile propelling apparatus comprising a barrel having inaddition to a breech chamber, a bore extending from the breech chamberto the forward extremity of the barrel, such bore having rifling and thegroove bore having three sections, namely, a cylindrical section at thefor: ward end of the bore and the lands calibre of which issubstantially equal to the calibre of the body of the projectile forwhich the barrel is designed and the groove bore diameter of which isnormal for such a lands bore, a cylindrical section next to and in frontof the breech chamber, such cylindrical bore section being of enlargeddiameter as compared with the groove bore of the first named cylindricalmuzzle section, and an intermediatesection longer than either of suchcylindrical sections and increasing gradually in diameter from thediameter of the cylindrical section at the forward end of the barrel tothe diameter of the enlarged cylindrical section at the breech chamberend of the barrel, each of the three said sections merging smoothly intothe adjacent section, the calibre of the lands bore being enlarged in adirection towards the breech chamber end of the barrel, and the landsincreasing in absolute height from ends nearest the breech chamber atfirst at a relatively quick rate of taper with relation to the axis ofthe bore and approximately proportionally to the increase in thepressure ordinates of the gas pressure-volume curve for the barrel, thelands then for a stretch being constant in absolute height, and thengradually decreasing in absolute height until a normal height isreached.

20. Projectile propelling apparatus comprising a rifled barrel having inaddition to a breech chamber and between the latter and the mouth of thebarrel a rifled bore the groove bore of which is formed in threesections, a cylindrical muzzle section, a cylindrical section next toand in front of said breech chamber and of a greater diameter than saidmuzzle section, and an intermediate section extending from the muzzlesection to the enlarged cylindrical section and increasing from thediameter of the former section to that of the latter, the lands borecalibre also being increased towards the breech chamber end of thebarrel at a different rate of taper (relative to the axis of the barrel)to said intermediate section of the groove bore, and to a point fromwhich the lands bore calibre remains for a distance constant, the landshere being of greater absolute height than are the lands at the mouth ofthe barrel, after which the lands bore calibre is again graduallyincreased, the rate of taper of this last named portion of the landsbore being such that, from their breech chamber ends to the nearest endof said constant portion of the lands bore, said lands increase inabsolute height approximately in proportion to the increasing latmuzzlesection of the groove bore being of a di ameter normal for the landsbore calibre of this section and which calibre is substantially equal tothat of the body of the projectile for which the barrel is designed.

21. Projectile propelling apparatus comprising 1 a barrel having, inaddition to the breech chamber, a rifled bore, the groove bore of whichis formed in three parts, namely, a cylindrical muzzle part of adiameter greater than the diameter of the body of the projectile forwhich the barrel is designed, a portion next to, and in front of, thebreech chamber end of a greater diameter than the cylindrical muzzlepart, and a third part joining the other two parts of the groove boreand increasing in diameter from the diameter of the muzzle part to thediameter of the part next to and in front of the breech chamber, thelands bore being, at the mouth of the barrel, of a calibre substantiallyequal to the diameter of the body of the projectile and also being,between the ends of the barrel, increased in diameter for a part of thelength of the lands and in a direction towards the breech chamber, suchlands bore then remaining of constant diameter for a further part of itslength and the absolute heights of such lands being over a portion oftheir lengths greater than the absolute heights of the lands in themuzzle part of the barrel.

22. Projectile propelling apparatus comprising a barrel having a breechchamber and being partly rifled, the lands bore being at the muzzle partof the barrel of a diameter substantially equal to that of the body ofthe projectile for which the barrel is designed whilst the groove boreis at this point of a diameter normal for such a lands bore, said grooveand lands bore being substantially constant in diameter and calibrerespectively for a distance from the mouth of the barrel and thengradually increasing in diameter towards the breech chamber end of thebarrel, but the lands bore increasing in diameter at a different angleto the axis of the barrel than said groove bore, and the lands enteringinto the groove bore between the ends of the portion thereof ofincreasing diameter, the bore being smooth and unrifled from the pointswhere the lands enter thereinto to the breech chamber end thereof, andsaid groove bore having a portion of constant enlarged diameter betweenthe tapered portion thereof and the breech chamber of the barrel.

23. A projectile propelling apparatus comprising a rifled barrel havinga breech chamber, and having a lands bore the diameter of which at themouth of the barrel is substantially equal to the diameter of the bodyof a flanged projectile which the barrel is designed to fire, whilst thegroove bore is, at'the mouth of the barrel, a normal amount greater indiameter than the lands bore, said groove bore being substantiallyconstant for a distance from the mouth of the barrel and then increasingin diameter in a direction towards the breech chamber and then being ofa constant enlarged diameter over a further portion of its length, saidlands bore also being increased in diameter in a direction towards thebreech chamber and the lands being at all places in their length of agreater absolute height (from the groove-bottoms to the top of thelands) than the minimum height required to prevent the flanges of thesaid projectile shearing from the lands in its passage through thebarrel under the action of a given propellant, and a given charge, thesaid varying absolute lands heights being determined. with reference tothe curve showing the specific lateral pressures with which the flangesof the said projectile will, in passing through the barrel under theaction of the respective propellant and charge, bear on the flanks ofthe lands.

24. A projectile propelling apparatus comprising a rifled barrel thelands bore calibre of which is at the muzzle of thebarrel substantiallyequal to the calibre of the body of the projectile which the barrel isdesigned to fire, and the groove bore of which barrel is at the muzzlethereof normal for the said lands calibre, said lands and groove boresbeing in their lengths increased gradually in diameter in a directiontowards the breech end of the barrel but said bores increasing atdifferent rates of taper to one another so that the lands attain amaximum height (which height is greater than the absolute height of thelands at the muzzle), and the lands then continuing at this height up toa point where they terminate,'at those ends nearest the breech chamber,abruptly from their maximum absolute heights.

25. Projectile propelling apparatus comprising a barrel having a breechchamber and in addition to the latter a bore consisting of three end toend coaxial sections, namely, a cylindrical muzzle section remote fromthe breech chamber and of substantially normal dimensions for thecalibre of the body proper of the projectile for which the barrel isdesigned, an enlarged cylindrical section adjacent and following thebreech chamber and such enlarged cylindrical section being between 20%and greater in cross sectional area than the said muzzle section, and aninteimediate section connecting the said cylindrical and muzzle sectionstogether and being relatively long as compared with said other sectionsand decreasing in diameter in a single continuous taper from thediameter of the said. enlarged cylindrical section to the diameter ofthe muzzle section.

26. Apparatus for propelling projectiles having a body provided withaxially spaced outwardly extending peripheral depressible flanges,comprising a barrel having a bore provided with rifling and in whichbore the lands calibre at the muzzle is substantially equal to thediameter of said projectile body whilst the groove bore at the muzzle isnormal for such lands calibre, the groove and lands bores both beingincreased in diameter gradually between the ends of the bore and in adirection away from the muzzle of the barrel, said lands being at a partbetween their ends of greater absolute height than they are at themuzzle, and said rifiing having a progressive angle of twist.

27. Projectile propelling apparatus comprising a barrel having a partlyrified bore, the lands bore being at the muzzle of the barrel of adiameter substantially equal to that of the body of a flanged projectilethat the barrel is designed to fire whilst the groove bore at the muzzleis normal for such lands bore, said groove and lands bore beingsubstantially cylindrical for a distance from the muzzle and eachincreasing in diameter gradually in a direction away from the muzzle,the lands bore having a lesser angle of taper relative to the axis ofthe bore than the groove bore, the lands attaining, at a distance fromthe muzzle, greater absolute heights than they have at the muzzle, andthen these lands being gradually decreased in height in a direction awayfrom the muzzle and entering the groove bore in the tapered partthereof, such groove bore having an enlarged cylindrical sectionextending rearwardly from the rear and larger end of its taperedsection.

HERMANN GERHCH.

